Buggy code:
public class InputCSPJFrame extends JFrame { private MainCSPSolver solver ; public InputCSPJFrame ( ) { } public void addClue ( SingleClue c ) { } public void updateCluesList ( ) { } @ SuppressWarnings ( "unchecked" ) private void initComponents ( ) { jScrollBar1 = new JScrollBar ( ) ; jTabbedPane1 = new JTabbedPane ( ) ; jPanel1 = new JPanel ( ) ; jLabel1 = new JLabel ( ) ; d1TF = new JTextField ( ) ; <START_BUG> d1TF . setText ( "1,2,3,4" ) ; <END_BUG> jPanel2 = new JPanel ( ) ; jScrollPane1 = new JScrollPane ( ) ; cluesJList = new JList ( ) ; jButton2 = new JButton ( ) ; jButton3 = new JButton ( ) ; solveBtn = new JButton ( ) ; setDefaultCloseOperation ( WindowConstants . EXIT_ON_CLOSE ) ; jLabel1 . setText ( "D1" ) ; d1TF . addActionListener ( new ActionListener ( ) { public void actionPerformed ( ActionEvent evt ) { jTextField1ActionPerformed ( evt ) ; } } ) ; GroupLayout jPanel1Layout = new GroupLayout ( jPanel1 ) ; jPanel1Layout . setHorizontalGroup ( jPanel1Layout . createParallelGroup ( GroupLayout . Alignment . LEADING ) . addGroup ( jPanel1Layout . createSequentialGroup ( ) . addContainerGap ( ) . addComponent ( jLabel1 ) . addPreferredGap ( LayoutStyle . ComponentPlacement . RELATED ) . addComponent ( d1TF , 361 , 361 , 361 ) . addContainerGap ( ) ) ) ; jPanel1Layout . setVerticalGroup ( jPanel1Layout . createParallelGroup ( GroupLayout . Alignment . LEADING ) . addGroup ( jPanel1Layout . createSequentialGroup ( ) . addContainerGap ( ) . addGroup ( jPanel1Layout . createParallelGroup ( GroupLayout . Alignment . BASELINE ) . addComponent ( jLabel1 ) . addComponent ( d1TF , GroupLayout . PREFERRED_SIZE , GroupLayout . DEFAULT_SIZE , GroupLayout . PREFERRED_SIZE ) ) . addContainerGap ( 230 , Short . MAX_VALUE ) ) ) ; jPanel1 . setLayout ( jPanel1Layout ) ; jTabbedPane1 . addTab ( "Variables<seq2seq4repair_space>Domains" , jPanel1 ) ; cluesJList . setSelectionMode ( ListSelectionModel . SINGLE_SELECTION ) ; jScrollPane1 . setViewportView ( cluesJList ) ; jButton2 . setLabel ( "REMOVE" ) ; jButton2 . setName ( "removeClueBtn" ) ; jButton2 . addActionListener ( new ActionListener ( ) { public void actionPerformed ( ActionEvent evt ) { jButton2ActionPerformed ( evt ) ; } } ) ; jButton3 . setLabel ( "ADD" ) ; jButton3 . setName ( "addClueBtn" ) ; jButton3 . addActionListener ( new ActionListener ( ) { public void actionPerformed ( ActionEvent evt ) { jButton3ActionPerformed ( evt ) ; } } ) ; GroupLayout jPanel2Layout = new GroupLayout ( jPanel2 ) ; jPanel2 . setLayout ( jPanel2Layout ) ; jPanel2Layout . setHorizontalGroup ( jPanel2Layout . createParallelGroup ( GroupLayout . Alignment . LEADING ) . addGroup ( GroupLayout . Alignment . TRAILING , jPanel2Layout . createSequentialGroup ( ) . addContainerGap ( ) . addGroup ( jPanel2Layout . createParallelGroup ( GroupLayout . Alignment . TRAILING ) . addComponent ( jScrollPane1 ) . addGroup ( jPanel2Layout . createSequentialGroup ( ) . addGap ( 0 , 231 , Short . MAX_VALUE ) . addComponent ( jButton3 ) . addPreferredGap ( LayoutStyle . ComponentPlacement . RELATED ) . addComponent ( jButton2 ) ) ) . addContainerGap ( ) ) ) ; jPanel2Layout . setVerticalGroup ( jPanel2Layout . createParallelGroup ( GroupLayout . Alignment . LEADING ) . addGroup ( GroupLayout . Alignment . TRAILING , jPanel2Layout . createSequentialGroup ( ) . addContainerGap ( GroupLayout . DEFAULT_SIZE , Short . MAX_VALUE ) . addGroup ( jPanel2Layout . createParallelGroup ( GroupLayout . Alignment . BASELINE ) . addComponent ( jButton2 ) . addComponent ( jButton3 ) ) . addPreferredGap ( LayoutStyle . ComponentPlacement . RELATED ) . addComponent ( jScrollPane1 , GroupLayout . PREFERRED_SIZE , 196 , GroupLayout . PREFERRED_SIZE ) . addGap ( 217 , 217 , 217 ) ) ) ; jTabbedPane1 . addTab ( "Clues" , jPanel2 ) ; solveBtn . setText ( "SOLVE" ) ; solveBtn . setName ( "solveCSPBtn" ) ; solveBtn . addActionListener ( new ActionListener ( ) { public void actionPerformed ( ActionEvent evt ) { jButton1ActionPerformed ( evt ) ; } } ) ; GroupLayout layout = new GroupLayout ( getContentPane ( ) ) ; getContentPane ( ) . setLayout ( layout ) ; layout . setHorizontalGroup ( layout . createParallelGroup ( GroupLayout . Alignment . LEADING ) . addGroup ( layout . createSequentialGroup ( ) . addGroup ( layout . createParallelGroup ( GroupLayout . Alignment . LEADING ) . addGroup ( GroupLayout . Alignment . TRAILING , layout . createSequentialGroup ( ) . addContainerGap ( GroupLayout . DEFAULT_SIZE , Short . MAX_VALUE ) . addComponent ( solveBtn ) ) . addComponent ( jTabbedPane1 ) ) . addContainerGap ( ) ) ) ; layout . setVerticalGroup ( layout . createParallelGroup ( GroupLayout . Alignment . LEADING ) . addGroup ( layout . createSequentialGroup ( ) . addComponent ( jTabbedPane1 , GroupLayout . PREFERRED_SIZE , 288 , Short . MAX_VALUE ) . addPreferredGap ( LayoutStyle . ComponentPlacement . RELATED ) . addComponent ( solveBtn ) . addContainerGap ( ) ) ) ; pack ( ) ; } private void jButton1ActionPerformed ( ActionEvent evt ) { } private void initVariables ( ) { } private void jTextField1ActionPerformed ( ActionEvent evt ) { } private void jButton3ActionPerformed ( ActionEvent evt ) { } private void jButton2ActionPerformed ( ActionEvent evt ) { } public static void main ( String [ ] args ) { } private JList cluesJList ; private JButton solveBtn ; private JButton jButton2 ; private JButton jButton3 ; private JLabel jLabel1 ; private JPanel jPanel1 ; private JPanel jPanel2 ; private JScrollBar jScrollBar1 ; private JScrollPane jScrollPane1 ; private JTabbedPane jTabbedPane1 ; private JTextField d1TF ; }

Fix:
d1TF . setText ( "4,5,6,7" ) ;